Finding the Fourth Proportional to 1,086.85, 1,499.79 and 621.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.85 : 1,499.79 = 621.10 : x
2. Step 2: Convert to fraction form
   1,086.85/1,499.79 = 621.10/x
3. Step 3: Cross multiply
   1,086.85x = 1,499.79 × 621.10
4. Step 4: Simplify right side
   1,086.85x = 931,519.57
5. Step 5: Solve for x
   x = 931,519.57/1,086.85
6. Step 6: Final answer
   x = 857.08